Thomas Molineaux, sometimes spelled Molyneaux or Molyneux, was an American bare-knuckle boxer and possibly a formerly enslaved person. He spent much of his career in the United Kingdom of Great Britain and Ireland, where he had notable successes. He arrived in England in 1809 and started his fighting career there in 1810. His two fights against Tom Cribb, widely viewed as the Champion of England, brought Molineaux fame even though he lost both contests. The result of the first encounter was hotly contested, with accusations of a fix. The second match with Cribb, however, was an undisputed loss. His prizefighting career ended in 1815. After a tour that took him to Scotland and Ireland, he died in Galway, Ireland, in 1818 at age 34.

Bare-knuckle boxing is a full-contact combat sport based on punching without any form of padding on the hands. The sport as it is known today originated in 17th-century England and differs from street fighting as it follows an accepted set of rules.